Geopolymer cement in the prior art has several undesirable properties or undesirable manufacturing steps. For example, a typical geopolymer cement requires an undesirable heating step near the temperature range of 450° C. to 750° C. to calcine the material, prior to mixing with water and aggregate materials. Also, undesirable low levels of heat (approximately 60 to 200° C.) are many times used to enact the polymerization in place of calcining. Similarly undesirable activators are used in the prior art to achieve strength, durability, and/or acceptable shrinkage characteristics. These disadvantages create unnecessary energy consumption, expense, and/or damage to embedded items. For example, chloride ion containing activators such as sodium or calcium chloride have been known to damage embedded items in prior art materials. As another example, Portland Cement requires a significant amount of energy/heat (in excess of 2000° C.) to create clinker prior to the grinding process.
As another example, Portland Cement Concrete requires a significant amount of energy and releases significant amounts of carbon dioxide into the atmosphere during production. To produce the majority of existing geopolymer concretes or geopolymer cements some degree of high heat calcination (e.g. from about 450° C. to about 750° C.) is required, prior to the addition of typical construction aggregate materials or water. Without a calcination heat treatment, prior art geopolymer concrete typically undergoes significant shrinkage during the strength development phase.
Calcining ingredients at a temperature ranging from about 400° C. to about 1200° C. degrees improves the quality of final mixtures, and reduces the caustic nature of alkali ingredients. One aspect of this invention removes this process thereby providing the industry with a concrete material that does not produce the carbon dioxide emissions created by applying a about 400° C. to about 1200° C. degree calcination process without compromising the desired qualities of the material, such as strength, durability, shrinkage, and modulus.
Activators consisting of chloride ion containing materials such as silic acid, or, potassium, calcium, or sodium salts produces strengths and desired quality characteristics. One advantage of the invention is that it does not require activators consisting of chloride ion containing materials and, thus, serves to provide the industry with a zero, or extremely low, chloride containing material without compromising the desired qualities of the material, such as strength, durability shrinkage, and modulus. One advantage of this approach is the reduction of damage caused by chloride ion attack on embedded metallic features in concrete, such as reinforcing steel. Of course, the materials and methods disclosed herein will still function with the use of these, and other, activators but it does not require them.
Oxidizing certain ingredients, and/or forming hardened materials under low heat consisting of from about 60° C. to about 200° C. degrees and then reducing these materials in size, produces desired quality characteristics in a construction material. One aspect of this invention provides the industry with a simplified production methodology, useable, for example, by the majority of new or current Ready Mix Concrete Suppliers.
Utilizing specific forms of Class C fly ash or Stainless Steel Ground Slag is appropriate to achieve desired quality characteristics in a construction material. This invention will function with these or similar materials. In addition, one aspect of this invention is that these materials are not required and, thus, the invention provides for use of a broader range of types of fly ash and Ground Blast Furnace Slag.
Calcined Kaolin Clay is appropriate for use in some construction materials. This invention will function with this and similar materials. In addition, one aspect of this invention is that it also utilizes non-calcined Kaolin Clay thereby further reducing Carbon Dioxide emissions by removing a substantial portion, or all, of the calcining process used with calcined Kaolin Clay. For example, one replacement for calcined Kaolin Clay or non-calcined Kaolin Clay, contemplated by the invention, is Purified Attapulgite Clay added at extremely low dosages of from 0.05% to 5% of the cementitious portion. Other similar materials can also be substituted for calcinated Kaolin Clay.